Method and apparatus for applying a coating



May 26, 1959 J. c. MILLER 2,888,176

METHOD AND APPARATUS FOR APPLYING A COATING Filed Jan. 21, 1954 llrlllllllllllllli I vs". i l

INV TOR. Jmr Furman Mmm.

.ATTY.

United States Patent @hice '2,888,175 Patented May 26, 1959 METHOD 'AND APPARATUS FOR APPLYING A COATING John Clifford Miller, Washington Township, Lucas County, Chio, assignor, by mesne assignments, to Donald Menhenett, Cleveland, Ohio Application January 21, 1954, Serial No. 405,317

2 Claims. (Cl. 222-396) which is portable and still has a capacity for a sutlicient Y/ quantity of the fiuid coating mixture to supply simultaneously more than one coating applicator or spray gun connected by separate flexible hoses to the container. For example, the method and apparatus of this invention may be adapted for applying by a spray lgun a p-rotective coating of a colloidal solid lubricant such as graphite and/or molybdenum disulfide, or the like, to machine or engine parts as they pass along an assembly line.

It is an object of this invention to provide a new, simple, efficient, effective and economic method and apparatus of applying a coating of microscopic and smaller solid particles from a relatively large refllable self-pressurized container.

Another object is to produce such a container which may be substantially completely emptied by means of the normal vapor pressure of a volatile fluid placed therein and also supply simultaneously a plurality of separate spraying discharge ports remote from the container.

Another object is to provide such an apparatus in which the valves, valve seats, and ducts connected thereto are non-corrosive, non-oxidizing and non-deteriorating with respect to highly polar organic solvent materials which may be in the fluid employed in the container.

Another object is to provide such an apparatus in which the release of the pressure therein is only at the discharge port remote from the container, namely, the nozzle of the applicator or spray gun, so that none of the material will become oxidized or evaporate in the ducts of the apparatus to clog the ducts when the apparatus is not 1n use.

Another object is to provide such an apparatus -in which the valves employed at the reiillable container portion of the apparatus are protected b-y guards or skirts mounted on the container, which skirts also may be used for handling and supporting the container.

Another object is to provide such an apparatus in which the discharge ports are independently adjustable so that different applicators may be used for dilerent purposes by different persons at the same time for applying the same coating from one container.

Another object is to provide such an apparatus with a safety pressure valve to prevent its explosion in the event the apparatus is placed in too warm a temperature.

Another object is to carry out a new, fast, quick and economical method of applying protective films to machine parts such as lubricating films of colloidal solid lubricating materials which may include rust inhibitors, by means of spraying the parts with a volatile carrier in which the coating ingredients are colloidally dispersed and dissolved.

Generally speaking, the apparatus of the present invention comprises a spun or pressed metal or welded steel bulbous type container of at least one gallon capacity, such as a cylinder with convex ends, or the like, such as for example a 5 gallon propane or butane household liquified fuel gas container, which container is provided ateach end with a valve assembly, one for filling and cleaning the container and the other for controlling the discharge of the contents placed in the container. The discharge valve assembly may also include a safety valve, and a siphon tube which is bowed inside of the container to extend to the lowest part of the inside of the container for completely emptying the same.

Attached to the control valve assembly may be a manifold for the connection of one or a plurality of iiexible hoses which extend to discharge ports of applicators or spray guns. These spray guns may be provided with long barrels having the nozzles at their ends incorporating needle type discharge valves. The long barrels of the spray guns are for extending into the interiors of the parts to be sprayed, such as cylinders for internal cornbustion engines. However, the spray gun and apparatus may be stationary and the parts to be sprayed may be moved past the gun assemblies.

Around the end valve assemblies on the container may be provided guards or skirts for protecting the valve assemblies from being jammed in the shipment of the container to the user or from the user back-to the factory for refilling, and for supporting and `locating handle grips for moving the container.

i The contents of the container are preferably dispersed in a highly volatile carrier liquid such as a low boiling fluoro-chloro aliphatic hydrocarbon compound (for example: dichlorodiuorornethane or trichloromonofluoro methane or a mixture thereof), which at normal room temperature, of say 60 to 80 F., will have a vapor pressure of from about 25 to about 60 pounds per square inch and preferably between about 30 and 35 pounds per square inch when confined inside a closed container. Suspended or dispersed in this Volatile liquid there is the colloidal solid coating material, for example: a liquid dispersion of colloidal graphite and/or molybdenum disulfide or other solid lubricating materials, which may contain also a solvent which contains an anti-rust inhibitor or other protective anti-oxidation chemical.

The above mentioned and other features and objects of this invention and the manner of attaining them are .given more specific disclosure in the following description of an embodiment, wherein:

Fig. l is a diagram of the complete apparatus of this invention with parts of the refillable container broken away, and showing a manifold for a plurality of extension hoses with one hose and its spray gun connected to said manifold;

Fig. 2 is an enlarged vertical section of the container of Fig. 1 showing also in section the end valves at the top and bottom of the container;

Fig. 3 is an enlarged vertical section of another form of rFefilling valve for the bottom of the container shown in Fig. 4 is an enlarged longitudinal vertical section of the spray gun shown in Fig. l with parts broken away; and

Fig. 5 is a further enlarged vertical section of the spray nozzle of the spray gun shown in Fig. 4.

Referring to Fig. l of the drawing, there is shown a welded cylindrical container 10 which has convex top and bottom end walls 11 and 12, respectively, to approach a design for the strongest pressure resistance with the lightest possible Weight. At the opposite ends of the cylindrical container in the center of the convex ends 11 and 12, respectively, may be provided a control valve assembly 20 in the end 11 and a refilling check type valve assembly 4t) in the bottom end 12. Surrounding these asserts valves there may be welded protective skirts 14 and 15, respectively, which are substantially cylindrical in shape and may be welded at 16 and 17 to the convex surfaces 11 and 12, respectively, of the container 10. The bottom skirt may be of larger diameter than the top skirt, shield or guard 14, so as to act as a base or support for the container with access to valve 40 only when in an inverted position as shown in Figs. l and 2. Although this valve 4t) is shown located in the bottom of the container, it obviously may be located in any other desired part of the container. Skirt 15 also may be equipped with casters, if desired. The top skirt 14 may be open along one side between the edges 18 for connection of the manifold 29 and/ or hose 30, and may also have handle grip apertures 19. The valve mechanisms 29 and 4t), respectively, may be screwed into threaded flanged holes or welded collars 21 and 41 therefor, respectively, located in the central ends of the convex end portions 11 and 12 of the container 10.

Referring now to Fig. 2, the upper cnd control valve assembly 2t) may be provided with a central duct 22 into which may be placed a Siphon tube 23, preferably of stainless steel, which is bowed or bent so that its end 24 tangentially touches the bottom of the container 10 near its lowest point which may also be adjacent the valve mechanism 40. The duct 22 is shown herein to terminate against a solvent resistant disk washer 25, such as of nylon, which may be raised by the pressure of the iluid in the container 10 as the manual valve 26 is screwed outwardly or upwardly to control or regulate the flow =from duct 22 through the duct 27 which discharges through a coupling fitting 28 for connection to a hose or a manifold 29 to a hose 30, the outer end of which hose 30 may be connected to an applicator or spray gun 60 having a needle type discharge valve 64 at its outer end. The manually operated flow regulating valve 26 is shown accessible through the open outer end of the skirt 14 and is preferably kept closed during shipping of the apparatus.

Also in the valve assembly 20 there may be provided an adjustable release or escape valve or device 31 which may be connected to the chamber in the container 1@ through a separate duct 32. The outer open end of the duct 32 may be closed by a ball type check valve 33 normally held closed by a compression spring 34 ad justably urged against the ball valve 33 by a screw plug 35 having a port 36 therein through which the pressure in the container may be released when it gets sufficient to operate the ball valve 33 against the action of the spring 34.

In the lower, bottom or opposite end of the container 10 (see Fig. 2), there may be provided a one way or check lling valve assembly 40, which may comprise a simple ball valve 42 normally closed by a spring 43. The outer end of the valve assembly 4t) is preferably provided with a manual removable cap, insert or plug 44 to prevent clogging or unwanted operation of the ball valve 42. V/hen the plug 44 is removed a filling nozzle (not shown) may be screwed therein, which by pressing the ball valve 42 open by an arm or by a greater pressure, may then iill the container when it is in the inverted position. ln this inverted position the Siphon tube 23 permits the lair and gas in the chamber to escape out through the flow valve 26, so that the coating liquid may be readily poured into the container 1t). Also, if desired, the whole valve assembled 20 and/or 4() may be removed frorn the bottom of the container to clean the inside of the container.

A disk type elack or check valve assembly 45, as shown in Fig. 3, may be used instead of the ball valve assembly 46, if desired, which assembly 45 may be provided with a pair of spring operated check valve disks 46 and 47 operated by separate helical concentric springs 48 and 49, respectively. The inner valve disk 46 is shown to be held by spring 48 over the openings 50 to prevent the liquid from the container from escaping and only permitting the introduction of more liquid Where it is under higher pressure than that already in the container; and the outer valve disk 47 held by spring 49 may be operated either by a nose or projection on the lling nozzle itself (not shown) or by suflcient pressure to permit the filling liquid to force its way into the chamber 52 of the valve mechanism 45. The seat for the disk valve 47 may be a ring seat 53 on a member 54 screwed into the valve assembly 45 and around which a removable manually operated cap 55 may be provided which may seat itself against a washer 56 for air tight protection of the valve disk 47, as well as protection of the threads 57 on the member 54 which cooperate with the filling nozzle (not shown).

Referring now to Figs. l, 4 and 5, a conventional type of applicator, namely a spray gun 60 with an elongated barrel, nose or tubular section 61, may be provided for the dispensing or" the coating material from the container 10. In this spray gun or applicator the exible hose 30 is fastened by conventional means with a duct 62 which extends through the tubular section 61 to the outer end or nozzle 63 provided with a needle type valve 64 and valve seat 65. Thus, during use the liquid or fluid to be sprayed as a coating is maintained under its own pressure from the container 10 up to the discharge port 66 in the nozzle 63 and is released only by the operation of the valve 64. lf desired, the edges of the valve 64 may have peripheral helical utings or grooves 67 to increase the turbulence of the fluid as it passes through the nozzle 63 and is discharged through the orice or port 66. The valve stem 68 for the nozzle valve 64 may extend back into the handle of the spray gun through a packing gland 69 where a spring 70 in a chamber 71 in the gun handle housing 72 normally maintains the valve 64 against its seat 65. For operating the valve stem 68 a diametrically extending pin 73 may be fastened through the stem 68 in the chamber 71, which pin extends through the sides of the housing 72. A trigger lever 74 pivoted on an axle 75 in the housing may push `against the pin 73 to operate the valve 64. The tension in the spring 70 may be adjusted by a screw tting 76 in the housing 72, access to which screw 76 may be had by removing a screw cap 77 at the base f end of the gun 60. Diierent types of spray nozzles 63 may be screwed on the end of the tubular section 61 to produce different spray patterns as desired.

The coating material or coating fluid 80 should be sufficiently volatile at room temperature to maintain a pressure of between about 25 and 60 pounds per square inch inside the container 10, hose 30, and ducts 22, 27 and 62 at all times at normal room temperatures, so that by operating the trigger lever 74 to open the valve 64, suicient pressure is obtained to form a spray through the nozzle orice 66 for the application of a thin breathlike iilm of material on the parts or articles to be coated. Such a container 1t) may be placed alongside a production line, and several operators with separate spray guns connected to hoses of different lengths may be stationed along the production line for coating the parts as they pass. The exible hose permits ready manuverability of the spray gun, which has an advantage over the previous hand type self-pressurized containers, wherein the heat of the hand of the operator is necessary for evaporating the volatile liquid, and which containers d-o not operate in the event they are inverted and the end of their Siphon tubes do not extend into the liquid in them. ln the present type container, a sufcient quantity of material may be stored for several days of substantially continued use by several people, and the containers are sufficiently rigid that they can be returned to a supplier for refilling while other containers are installed in their place. The replacement may be accomplished by closing the central valve 26 of the empty container, disconnecting the ttings 28, and connecting the full container to the ttng 28 and opening its control valve 26, but generally the Whole apparatus including the applicators is replaced so that reflller or supplier may clean and check the spray guns.

In order to maintain the required pressure in the container at room temperature so that no heating nor additional apparatus is required, the fluid 80 contains between about 45 and 98%, and preferably 75 to 95%, by weight of the propellant uid which has a boiling temperature below that of room temperature. For example, some propellants which may be employed are carbontetraiiuoride, monochlorotrifluoromethane, monochlorodiuoroethane, dichlorotetratluoroethane, dichloromonouoromethane, ethyl chloride, ethylene oxide, trichloromonouoromethane, and the like.

The colloidal solid coating materials are usually prepared in liquid concentrates which are dispersable in the highly volatile carriers and propellants. Some such solids lfor lubricating coatings include colloidal graphite, colloidal molybdenum disulfide, talc, vermiculite, tungsten disulfide, zinc oxide, calcium oxide, mica, silver sulfate, lead iodide, molybdenum telluride, tungsten selenide, molybdenum Iselenide and similar crystalline plate like compounds in which the metallic atoms are arranged in plane layers with a layer of non metallic atoms of elements of the group sulfur, selenium or tellurium on each side of the layer of metallic atoms.

The amount of solid colloidal particles present in the fluid 80 is generally between about .02% and 7% by weight, and preferably between about .5% and 2.5% by weight. These compounds, however, also may include a binder, such as methyl cellulose, ethyl cellulose or other cellulose or gumming material, so that the particles will stick to the surface to which they are applied or sprayed. The percentage of such binders is usually between about .02% and 4%, preferably between about .1% and 1%, by Weight of the entire composition.

The liquids in which these solids may be dispersed include organic solvents preferably boiling below about 100 C. and above about 20 C. including hydrocarbons such as petroleum ethers to light oils, hydrocarbon halides such as methylene chloride, alcohols such as methanol, ethanol and isopropanol; ethers; ketones; esters; etc. The amounts of such solvents or dispersants in the nal uid 80 is between about 1.5% and 20% by weight and preferably between about 4 land 16% by weight.

If desired, the entire composition also may contain between about .001% and .01%, and preferably .0005 and .0010% by weight of a rust inhibitor, but such is not an essential ingredient of the lubricating coating composition.

Accordingly, the method of this invention of placing the dry lubricant on machine parts, particularly before they are assembled, to prevent their dry rubbing against each other until they may be lubricated by oil, is a new and practical method for applying a lubricant never before employed in such an economical, easy and practical manner. The present apparatus is particularly adapted for mass production in places where large areas are to be covered in relatively short periods of time with a dry lubricating coating material. The film which may be coated may either be a dry or wet lm depending upon the carrier and the liquid in the concentrate which is 6, dissolved in the propellant, before it is inserted into the container 10 of the apparatus. The dispersant or carrier liquid may contain in itself a lubricating oil or a liquid lubricant, as well as solid lubricant particles.

If desired, as many as six discharge ports or spray guns may be connected onto a manifold, all of which may be operated at the same time and still give the desired pressure on all six of the guns, although there are only three such ports shown on manifold 28 in Fig. 1.

The ttings of the device are preferably made of brass or stainless steel in order to prevent oxidation and to resist the action of the solvents employed in the uid 80. This is true of the Siphon tube 22. Regarding the exible hose 30, it should be a pressure hose and may contain a particular synthetic plastic or metallic liner and/or sheath to prevent the solvents from dissolving the insides of the hose or loosening particles therefrom which may cause clogging of the spray gun nozzle.

The relief valve 31 may be set at a pressure of 250 pounds per square inch which is way below the breaking pressure for the container 10 and its fittings, and which pressure is above all normal operating pressures which would occur in the container.

While there is described above the principles of this invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of this invention.

What is claimed is:

1. An apparatus for dispensing a normally volatile liquid which will vaporize at room temperature, comprising: a multi-gallon container, said container having a one-way valved filling opening in a lower portion thereof, said container further having a second opening in an upper portion thereof having a pressure release valve operatively associated therewith, a Siphon tube extending from said opening to the bottom of the container, and a valved conduit extending outwardly from said opening and terminating in a manifold adapted to be connected to one or more spray guns.

2. An apparatus according to claim 1 wherein said second opening has a valve assembly containing both said pressure relief valve and said valved conduit connected to said siphon tube.

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